In terms of the mechanism itself, there are at least three: reverse clicky (used to be standard on most of their basic hosts) forward clicky (seems more common now) and the twisty S7, which is press for momentary/twist for constant on.
The clickies feel pretty similar in terms of how much pressure is required to activate them. In comparison to the McClicky on my MD2, the Solarforce forward switches feel somewhat heavier/spongier.